ᐅ Improving the Efficiency of Solar Thermal Systems

Created on: 11 Sep 2020 07:37
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BenutzerPC
We have a 300L (79 gallons) buffer tank, and our heating is supplied by district heating. Currently, the heating boost is set to run from 5:30 a.m. to 10 p.m. I have read that it is better to start the heating boost from around midday to optimize the efficiency of the solar thermal system, since the water is colder and can absorb energy more effectively. That sounds reasonable to me.

My question is: How much can I reduce the district heating boost time for domestic hot water production? At the same time, I want to ensure that Legionella prevention is adequately addressed. Currently, my domestic hot water temperature is set to 65°C (149°F). Would it theoretically be sufficient to run the heating boost for about 1 hour per day to raise the tank temperature to 65°C (149°F) and thus prevent Legionella?

What would be the most efficient approach regarding the solar thermal system in this context?
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Lumpi_LE
12 Sep 2020 08:02
Trying to improve anything on a street is like casting pearls before swine. In summer, you have too much anyway, in winter, practically nothing.
K1300S12 Sep 2020 08:11
The optimization likely consists of avoiding charging the storage tank with solar thermal energy during the summer.
Mycraft12 Sep 2020 09:30
This is how it looks, because if you just let it run, both will keep heating the storage tank whenever it’s empty, regardless of whether it makes sense or not. The district heating kicks in after the morning shower, and the solar thermal system only later, but by then you’ve already spent the money. The goal here is to prevent that.

The solar thermal system should heat all the water as long as there is sunlight. District heating should only start when there is no longer a chance to draw energy from the solar thermal system to fill the storage tank.
K1300S12 Sep 2020 10:03
That is exactly why my heating system only charges the storage tank in the morning before getting up, as there is no sunlight at that time yet.
Mycraft12 Sep 2020 10:50
Is the sunlight in the afternoon not enough to last through the night, or is there extensive showering in the evening that then empties the storage tank?

Just out of curiosity...
K1300S12 Sep 2020 15:01
More the latter... once the daughter is in bed, the wife takes a bath. In the morning, there is just enough time left for brushing teeth, but not for a proper shower.

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